The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
Some internal combustion engines include engine control systems that deactivate cylinders under specific low load operating conditions. For example, an eight cylinder engine can be operated using four cylinders to improve fuel economy by reducing pumping losses. This process is generally referred to as active fuel management (AFM). Operation using all of the engine cylinders is referred to as an activated mode. A deactivated mode refers to operation using less than all of the cylinders of the engine (one or more cylinders not active).
In the deactivated mode, there are fewer firing cylinders. As a result, there is less drive torque available to drive the vehicle driveline and accessories (e.g., alternator, coolant pump, A/C compressor). Engine efficiency, however, is increased as a result of decreased air pumping losses due to the deactivated cylinders not taking in and exhausting fresh intake air.
A lifter oil manifold assembly (LOMA) can be implemented to activate and deactivate select cylinders of the engine. The LOMA includes a series of solenoids that are used to control oil delivery to hydraulically switching lifters. The solenoids are selectively energized to enable hydraulic fluid flow to the lifters to inhibit valve lifter operation, thereby deactivating the corresponding cylinders. The solenoids remain energized while the engine operates in the deactivated mode. The solenoids are de-energized when reactivation of the deactivated cylinders is desired.